Abstract

This work reports the investigations of both etch characteristics and mechanisms for the (GST) thin films in the inductively coupled plasma. The GST etch rates and etch selectivities over were measured as functions of the mixing ratio (43%–86% Ar), gas pressure , and source power . Langmuir probediagnostics and zero-dimensional (global) plasma modeling provided the information on plasma parameters and behaviors of plasma active species. From the model-based analysis of surface kinetics, it was found that with variations of the mixing ratio and gas pressure, the GST etch rate follows the changes of Cl atom density and flux but contradicts with those for positive ions. The GST etch mechanism in the -containing plasmas represents a combination of spontaneous and ion-assisted chemical reactions with no limitation by ion-surface interaction kinetics such as physical sputtering of the main material or the ion-stimulated desorption of low volatile reaction products.